1. Field of the Invention
The invention relates to a circuit testing apparatus, and more particularly, to a circuit testing apparatus utilizing a logic tester for testing the DC voltage of the integrated circuits.
2. Description of the Related Art
Usually, the integrated circuit (IC) test after fabrication is necessary to assure the quality of the integrated circuit. The manufacturers thus determine whether the integrated circuit is qualified according to the test result and provide for the merchants.
FIG. 1 is a schematic diagram of a conventional apparatus for testing the integrated circuit. A logic tester 10 is provided for testing a device under testing (DUT) 22. The device under testing 22, which is preferably provided on a circuit board with the device under testing (DUT board) 20, may be an integrated circuit (IC) under test.
The input state and the logic level of the device under testing 22 are commonly provided prior to the use of the logic tester 10 for measuring the DC voltage of the device under testing 22. A function generator 12 of the logic tester 10 sequentially inputs a single testing code to the input pin of the device under testing 22. The device under testing 22 receives the single testing code from the input pin and generates a corresponding DC voltage in the output pin. The logic tester 10 interrupts the clock of the inner logic to measure the DC voltage from the output pin. A precision measurement unit (PMU) 14 is utilized to specialize the internal setting and measure the DC voltage. Finally, with the result of the measurement, it is determined whether the device under testing 22 is qualified or not. Through the conventional process, it is a waste of time to transfer only one testing code each time and to interrupt the clock in the logic tester 10 while the DC voltage is measured. Whereupon, a long testing time is required and the efficiency for testing the device under testing 22 is further influenced.